Property tax not paid

my neighbours not paying their property tax(commercial building, collecting rents 60K /month) 

from the last three years. owner age is 95years. building age is 50years(building constructed without pillars, G+1 building) presently the building position is in a dangerous position and likely to fall @ any moment of time. One month before GHMC issued a notice under section 459 of HMC act. Till now GHMC has not  collapsed nor  taken any action. what should i do......?